Abstract: Design of the proportion of trousers structure, there is a set of empirical formula and fixed-inch, which is accumulated through long-term practice and experience, there are certainly reasonable. However, a variety of pants for a rich and varied styles, appropriate ratio of distribution is a very difficult problem to master; designers are often subject to such empirical formula, while the constraints of the design ideas, limiting the innovative design of the play. Article describes a new method of structural design of trousers - decile method, it is based on the proportional relationship between the body structure, by setting the "crotch position marking" and "crotch-bit Adjustment," to use equal portions of the corresponding designed Trousers the proportion of parts of the structure of relationships; under the pants shape changes and to the basic structure of pants patterns, based on changes in the structure design of various types of pants style. This method avoids the complex calculations and experience-inch, the structure is more reasonable, comfortable fitness is good, change the design flexible, and feasible, the design accuracy and efficiency improved significantly.